The objective of this study was to determine the effect of Verticillium dahliae
Kleb. on cotton yield and fiber technological properties, relationships among to
disease and seed cotton yield, fiber yield and fiber technological properties and also
determine susceptible and tolerant cotton varieties. The study was conducted in the
Southeastern Anatolia Agricultural Research Institute’s experimental area during
2004-2006. The experiment was arranged as a randomized split block design with
four replications. Main plot consisted of infected and non-infected area, sub-plot
consisted of varieties. In this study 10 different commercial cotton varieties were
grown to test the verticillium wilt performance. The results indicated that there were
significant differences among varieties for all of the investigated characteristics. Area
differences were significant for all of the investigated traits except ginning
percentage. The results of the non-infected area showed that there were decreasing
with regard to foliar disease index (FDI), vascular disease index (VDI), vascular
disease rate (VDR), first picking percentage, fiber fineness, micronaire and
yellowness; while increasing with regard to seed cotton yield, fiber yield, fiber
length, strength, elongation, uniformity, reflectance and spinning consistecy index.
Only ginning percentage was unaffected from area differences. With planting cotton
varieties in non-infected area there were 323.60 kg ha-1 increase for seed cotton yield
and 114.50 kg ha-1 for lint yield. Disease led to a decrease (7.86%) in seed cotton
yield and (6.73%) in fiber yield. The results of this study indicated that GW-Teks,
GW-Golda and Carmen varieties were tolerant; while Maraş 92, Sayar 314 and
Stoneville 453 were sensitive in terms of FDI, VDI and VDR and tolerant varieties
can be used as parents in Verticillium breeding programs.

Cassava (Manihot esculenta Crantz) is currently the most important upland crop
of Cambodia, but information on yield variations and causal factors which is
important for efficiently targeting efforts to increase production is still lacking. The
objectives of this study were to determine the yield variations and causal factors for
cassava production in Kampong Cham province in Cambodia. Forty five households
in four production zones were selected for the study. A farm survey employing semistructured
interviews, combined with field visits, were used for the collection of
information on farmers’ practices in cassava cultivation, while crop cutting was done
to provide estimates of cassava yields. The data were analyzed for yield variations,
yield gaps and causal factors. The results showed large variations in yield among
farmers’ fields, ranging from 12.7 to 37.2 t ha-1. The fields were divided into five
yield categories, with the mean yields of the lower four categories ranging from 76.0
to 34.2% of the maximum yields, with corresponding yield gaps ranging from 8.9 to
24.4 t ha-1. The main yield constraints identified were soil nutrient deficits, short crop
duration and weed competition. The highest yielding fields had no production
constraints, but the number and/or the level of constraints increased in fields with
lower crop yields. However, for different fields with similar yield levels, the main
production constraints sometimes differed. The results clearly indicated that there are
opportunities for yield improvement and narrowing of yield gaps through the
adoption of field specific improved technologies and management practices.

Conventional procedures are inadequate for optimizing the concentrations ofnutrients to increase the sugar yield. In this study, an artificial neural network(ANN) was used to optimize the Ca, Mg, N, K and Na content of the storage rootto increase sugar yield (Y) by increasing both sugar content (SC) and root yield(T). Data from three field experiments were used to produce a wide range ofvariation in nutrient content, SC and T. In the training phase of the ANN, R2 was0.91 and 0.94 for SC and T, respectively. The high R2 values obtaineddemonstrating the ability of the ANN to predict SC and T. The obtained optimumvalues were 0.37%, 0.35%, 0.97%, 4.67 (meq/100 g) and 0.33% for Ca, Mg, N, Kand Na, respectively. Optimization increased the potential Y by 17%.

Many soils are contaminated by heavy metals, with arsenic posing serious
environmental threat. Enrichment of soil with phosphate is believed to reduce the
arsenic toxicity. However, only a few attempts have already been conducted towards
understanding the precise role of phosphate in controlling As toxicity. Moreover,
there is no adequate information on the effect of phosphate on As-induced oxidative
stress, a major contributor of As toxicity in plant system. Τhe present study aims to
determine the effect of varying concentrations of phosphate on As-mediated
oxidative stress in pearl millet (Pennisetum typhoides). Our study revealed that a
concentration of 100 μM of phosphate was able to protect the test plant from As
(100μM)-mediated oxidative stress, as evident from the data on growth and lipid
peroxidation. This novel finding was further supported by the increased chlorophyll
content of the test plant raised in phosphate supplemented media. Phosphatemediated
improvement of antioxidant enzymes, such as SOD (superoxide
dismutase), CAT (catalase), and APX (peroxidase), could be a crucial factor in
regulating As-induced oxidative stress in pearl millet. The results of the present study
suggest that availability of phosphate in the surrounding media has a clearly pivotal
role in the generation of oxidative stress in P. typhoides exposed to As

Physical, chemical and biological attributes of soil surface are significantly affected
by tillage practices and crop rotation. The objective of this study was to determine the
short-term (2006-2009) effects of conventional and conservational tillage practices on
selected soil physical properties of a heavy clay soil under two wheat-corn and wheatlegume
rotation in a semi-arid Mediterranean Region. Treatments included
conventional tillage with residue incorporated in soil (CT1), conventional tillage with
burned residue (CT2), reduced tillage with heavy tandem disc-harrow (RT1), reduced
tillage with rotary tiller (RT2), reduced tillage with heavy tandem disc harrow fallowed
by no-tillage (RNT) and no tillage (NT). Disturbed and undisturbed soil samples were
collected to determine saturated hydraulic conductivity (HC), bulk density (BD), mean
weight diameter (MWD), available water content (AWC) and total porosity at 0-10,
10-20 and 20-30 cm depths. The highest HC values of 0-10 cm and 10-20 cm depths
were obtained with CT1 (9.70×10-6 m s-1, 8.74×10-6 m s-1) and CT2 (9.39×10-6 m s-1,
8.58×10-6 m s-1) applications. CT2 treatment destructed the soil aggregates and resulted
in greater bulk density and low total porosity at 0-10 cm depth. The available water
content at 0-10 cm depth was significantly reduced with the CT1 (P<0.01) and CT2
applications (P<0.05). Although three years of no-tillage application in clay rich soils
caused higher bulk density and low porosity, increase in MWD is an indication of soil
and water conservation. Therefore, no till and reduced till applications should be
adapted to the farmers’ conditions for sustainability in agriculture..

The effect of grafting and post-grafting temperature on the plant development of
two watermelon cultivars at transplantation and on subsequent fruit quality was
studied. Watermelon cv. Sugar Baby and Crimson Sweet were self-rooted
or grafted onto rootstock RS 841 F1 (Cucurbita maxima × C. moschata) or bottlegourd
[Lagenaria siceraria f. clavata] (year 1), plus L. siceraria f. pyrotheca
(year 2). After grafting, plants were held at 8 oC or 16 oC (minimum) until
transplantation (28-29 days), at which stage growth was compared with that of the
self-rooted control held under the same conditions. Plants were planted in the field
and fruit quality assessed at harvest. At the time of transplantation in year 1, plants
at 16 oC were taller and had a higher total fresh weight than those at 8 oC. The
grafted plants of both cultivars were taller and had a higher leaf area and fresh
weight than the self-rooted plants, irrespective of rootstock. In year 2, the grafted
plants of both cultivars had better development (height, leaf area, leaf number,
fresh weight) than self-rooted plants. The plants of Crimson Sweet × L. siceraria
f. pyrotheca were taller than those of the other two scion-rootstock combinations,
irrespective of temperature. Mean fruit weight at harvest was higher in grafted
plants than in self-rooted plants, and sugar content varied with scion-rootstock
combination. Grafting of watermelon results in better plant growth by the time of
transplantation, whereas the scion-rootstock combination affects fruit quality. A
minimum temperature of 16 oC is indicated during the post-grafting stage.

Quantification of the Nitrogen (N)-supplying capacity of organic manures
provides an important insight into more effective N management practices. The aims
of this study were to determine the potential N mineralization of cow manure (CM),
poultry manure (PM), urea fertilizer (UF) and the combined use of cow manure +
urea fertilizer (CM + UF) for silage maize (Zea mays L.) in a calcareous soil under
field conditions. Selected soil samples were collected after different N sources
application, and mineral N (NO3--N and NH4+-N) was determined for a total of 110
days of field incubation, using the buried bag technique. Poultry manure-treated soils
had significantly higher total N mineralization (244 kg ha-1) than CM (109 kg ha-1),
UF (138 kg ha-1) and CM + UF (141 kg ha-1) treated soils. However, N availability
was greater in UF (69%) and PM (61%) treated soils than that of CM + UF (47%)
and CM (28%) fertilized soils. Shoot dry matter of maize and N uptake were
considerably higher in PM treated soil than in UF, CM and CM + UF soils.
Nevertheless, maize N recovery was significantly higher in urea soils (60%) than in
PM (42%) and CM + UF (37%) soils followed by CM soil (15%). In conclusion, our
data indicated that PM and the CM + UF that released N slowly resulted in high
maize silage production, N uptake and N recovery following their application in
these calcareous soils with low SOM content and N availability.

Water use efficiency (WUE) reflects the coupling of the carbon and water cycles
and is an effective integral trait for assessing the responses of vegetated ecosystems
to climate change. In this study, field experiments were performed to examine leaf
WUE (WUEleaf) in response to changes in CO2 concentration and other
environmental variables, including soil moisture and air temperature. We also used
yield of maize and soybean, soil water content and precipitation data to calculate
water use efficiency at the level of grain yield (WUEgrain) in a manner that enabled us
to analyze the effects of climatic factors on WUEgrain. The results showed that the
WUEleaf measurements of maize and soybean plants were negatively correlated with
soil moisture and air temperature. At a photosynthetically active radiation (PAR) of
1.600 μmol m-2s-1, increasing ambient CO2 concentrations (from 400 to 800 μmol
mol-1) improved WUEleaf by 52.0% and 75.8% for maize (a C4 species) and soybean
(a C3 species), respectively. Increased annual precipitation stimulated maize WUEgrain
up to levels of approximately 500-550 mm, although maize WUEgrain decreased when
annual precipitation exceeded 550 mm. It appears that 400-450 mm is an economical
evaportranspiration (ET) for spring maize in Chaoyang area of northeast China. For
soybean, more water often reduces WUEgrain, and there is a linear relationship
between changes in WUEgrain and changes in annual temperature. The different
responses of WUEgrain and WUEleaf to climate change suggest that caution should be
taken when attempting to up-scale WUE from leaf to grain or biomass levels.